i'll try to breakit down...
1. Why the speed to be flown after engine failure and subsequent drift down is LRC(several checklists mention that) and not MRC since range is the worst affected flight parameter?
2. Does time has any significance in this(as we know LRC is a faster than MRC and would take a lil less time), since ETOPS also imposes time limits at OEI cruise speed? If so how does it play its part?